How Accurate is the Huawei Air Quality Monitor? New Test!

When I started building DIY air purifiers in Beijing to protect my lungs from this…

…I wanted to test the air in my home, but particle counters were really expensive. Most cost around $1,000 or $2,000 dollars.

But then there was the Dylos, which I bought for about $260.

Just like air purifiers, the technology behind particle counters is actually really simple and cheap. The detector is just a laser and a photo receptor—nothing super expensive. Fortunately for data nerds like me, the market has capitalized on this basic fact and exploded with even-more-affordable air quality monitors.

Smart Air tested two of these more affordable particle counters—the Laser Egg and the Air Visual Node—against the Dylos. The results were pretty good!

Results

Overall, the Huawei (blue line) tracked the official PM2.5 numbers (orange line) pretty well. However, the Huawei consistently undercounted. At worst, the Huawei undercounted by 52 micrograms. That error is 5 times the WHO annual limit for PM2.5, so that’s pretty big.

On the whole, the Huawei correlated highly (r = 0.88) with the official numbers, although it performed on the low end of all the particle counter Smart Air has tested so far. I should warn that the Huawei test was done at a different time and location than the earlier tests, so some of the differences could be due to the testing.

Next I analyzed the average deviation—on average, how many micrograms of discrepancy was there between the particle counter and the official numbers? This is where the Huawei was clearly the worst performer. It had double the average error of the other machines.

Bottom Line: How Accurate Is the Huawei Air Quality Monitor

All in all, the Huawei scored worse than the Egg, Node, and Dylos. However, the correlation with official PM2.5 was high, and it’s certainly good enough to tell you if the air you’re breathing is toxic or safe, 10 micrograms or 200 micrograms. From my perspective, the Huawei is sufficiently accurate to:

· Test whether a purifier is making your room air cleaner

· Tell whether your air is in the good range or unhealthy range

But it is not sufficiently accurate to interpret the numbers 100% literally. If it says 100 micrograms, it could easily be 80 or 120 micrograms. There are other more accurrate pollution monitors out there which cost only a little more. Yet for most everyday uses, the Huawei will suffice.

Breathe safe!

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Thomas is an Associate Professor of Behavior Science at the University of Chicago Booth School of Business and the founder of Smart Air, a social enterprise to help people in China breathe clean air without shelling out thousands of dollars for expensive purifiers.

Even with the same sensor, there are still other factors at play:
1) The airflow through the sensor, and overall design of the device
2) The calibration in the laboratory prior to selling the device
3) The software used to convert the raw particle count to concentration (all particle counters give only a ‘particle count’ reading, it is the job of each sensor’s software to convert this into meaningful information)

Reply

2019-01-27 6:35 pm

Matthew

I have a Sndway air quality monitor that I bought from AliExpress over a year ago for $40 and I’m very happy with it. It just gives the raw pm2.5 count and uses the same Plantower sensor as all these other laser monitors. It gives me readings that are very close to those from Thailand’s Pollution Control Department stations. These things are basically something anyone with a soldering iron and a basic knowledge of electronics could assemble for $20. Why doesn’t Smart Air produce its own and sell them on the website?

Good question Matt! We’ve thought about making our own particle counters, but we unfortunately haven’t had the time to get round to this. One of the big problems with counters is that they can become ‘cans of worms’ since it’s not just hardware but software as well. Having said that, there are lots of low cost ones out there like you say, and we’re looking at some options right now for how we can bring a lower cost option to the market!

Reply

2019-02-01 12:17 pm

Fandor

@Paddy Robertson : are you planning to test the Sndway ? It’s rather cheap and those who buy it seem pretty happy !

About Smart Air

Smart Air is a social enterprise based in China, India, Mongolia and the Philippines that creates simple, no-nonsense air purifiers and provides free education to combat the impacts of air pollution.
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